In many wells used for the production of oil, water, gas and the like, it becomes necessary from time to time to treat such wells to improve their permeability, to inject materials which can protect metallic components of the well from corrosion and which can protect the formation, especially the formation near the wellbore, from scaling as a result of the production of fluids from the well.
Many of these operations are used more frequently in oil wells and in gas wells than in water wells.
In many instances, formations which contain valuable oil or gas products may be so impermeable that the production of fluids from these formations, either initially or after a period of production is impractically slow. In such instances, a variety of techniques have been used to improve the production rate. One technique is the use of fracturing. This procedure requires that a pressure greater than the formation pressure be imposed on the formation to create fractures into the formation. While this technique has been effective in many instances, it is limited in that it creates a flow path only through the areas fractured. This leaves major portions of the formation untreated to improve the permeability.
Acid treatments have been used with and without foaming and emulsifying agents to pass acids and the like into the formation. Unfortunately, because of the limited permeability initially present or present at the time of treatment, these materials are difficult to inject into the formation for any substantial distance without the injection of unduly large volumes of the treating material.
As a result, a continuing effort has been directed to the development of methods which are effective to inject treating solutions into subterranean formations for a substantial distance without the use of unduly large volumes of treating fluid.